python-用两个不同列表中的值替换列表中的布尔值 [英] python - replace the boolean value of a list with the values from two different lists

问题描述

我有一个列表，其中包含布尔值，例如

I have one list with boolean values like

lyst = [True,True,False,True,False]

和两个不同的列表，例如:

and two different lists for example like:

car = ['BMW','VW','Volvo']
a = ['b','c']

我只想将car中的值替换为True，并将a中的值替换为False. 或使用lyst中的顺序以及car和a中的值创建一个新列表. 结果应为

I just want to replace True with the values from car and False with the values from a. or make a new list with the sequence from lyst and values from car and a. The result should be

[BMW,VW,b,Volvo,c].

到目前为止我的代码:

for elem1,elem2,elem3 in zip(lyst,car,a):
    subelem2=elem2
    subelem3=elem3
    if elem1 != True:
        result_list.append(subelem2)
    else: 
        result_list.append(subelem3)

但是创建的列表匹配项长于5.

but this creates a list match longer than 5.

我该怎么做?

推荐答案

car = iter(car)
a = iter(a)
[next(car) if item else next(a) for item in lyst]

---

好吧，我无能为力:

---

Ok, I couldn't help myself:

car = iter(car)
a = iter(a)
[(flag and next(car)) or next(a) for flag in lyst]

这利用了一些布尔表达式功能:

This makes use of some boolean expression features:

• 如果第一个操作数为False，则布尔值and表达式将不计算第二个操作数
• 如果两个操作数均取值为True，则布尔and表达式将返回第二个操作数(实际对象)
• 布尔值or表达式将返回第一个计算为True的对象

• a boolean and expression will NOT evaluate the second operand if the first operand is False
• a boolean and expression will return the second operand (the actual object) if both operands evaluate to True
• a boolean or expression will return the first object that evaluates to True

如果car或a中的任何项目评估为False，则可能会出现问题.同样，这不如第一个解决方案中的三元可读.

A potential problem would be if any items in car or a evaluate to False. Also this isn't as readable as the ternary in the first solution.

但这很有趣.

我想我会补充一点，在再次查看之后，我可能不应该重新分配原始列表名称-我应该为迭代器名称选择其他名称.一旦耗尽，迭代器就无法重置，并且由于重新分配了列表名称，因此原始列表信息也会丢失.

I guess I'll add that after looking at this again, I probably shouldn't have reassigned the original list names - I should have chosen something different for the iterator names. Once exhausted, the iterators cannot be reset and since the list names were reassigned, the original list information is lost.

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